Data Execution Prevention, any technique to protect data from being executed as code, thus preventing some exploits.

learn more… | top users | synonyms

-1
votes
1answer
62 views

Why should I use ROP for exploit dev? [closed]

Return Oriented Programming is a technique for bypassing DEP which based on ret2libc.. ROP is used for formatting the API function parameters in order to make a reliable shellcode.. I dont get ...
2
votes
1answer
65 views

Are stack buffer overflows even possible in this instance?

Let's say there is a C program that simply takes a string argv[1] and uses sprintf to copy it in a finite buffer. Classic stack buffer overflow. Let's even say the program is more complicated, ...
2
votes
1answer
144 views

How can I check if a Mac application has NX or ASLR enabled?

According to Wikipedia, the NX bit is set for all x64 binaries: OS X for Intel supports the NX bit on all CPUs supported by Apple (from 10.4.4 – the first Intel release – onwards). Mac OS X 10.4 ...
3
votes
1answer
396 views

How does SEH based exploit bypass DEP and ASLR?

I am new to structured exception handling based exploits. Why don't we put our return address directly in SE handler to jump to our shellcode? (with no safe SEH) Can anybody explain the reason of ...
1
vote
3answers
127 views

How does Windows know which part of memory is “intended to hold data only”?

I'm learning about DEP implementations, now I'm trying to figure out how does the OS know which part of memory is intended to hold data only?
1
vote
2answers
193 views

ROP Gadgets from executables?

I noticed that exploits which use Return Oriented Programming always find the gadgets in libraries. I wonder if it is possible to use gadgets from the executable (.exe) itself?
0
votes
1answer
167 views

Different types of segmentation faults in Linux [closed]

In Linux, when the NX-bit triggers the segmentation fault seems to be "error 15", whereas a more typical error, such as attempting to read from invalid memory, results in "error 7", (seen from dmesg ...
10
votes
2answers
4k views

How “leaking pointers” to bypass DEP/ASLR works

I was wondering if anyone could give me some clues on how "leaking pointers" to bypass DEP/ASLR work. I read here: The only way to reliably bypass DEP and ASLR is through an pointer leak. This ...
4
votes
1answer
290 views

What attacks does a W^X policy prevent against?

Write xor Execute (W^X) is a policy that a block (page) of memory cannot be marked as both writeable and executable at the same time. What attacks does W^X prevent, with and without the following: ...
5
votes
1answer
269 views

Hardware enforced DEP on different CPUs

Are there any differences how hardware DEP is implemented on CPUs from different manufacturers (Intel, AMD, nVidia, Texas,...)? Are there any significant differences how hardware DEP works on x86 ...
5
votes
2answers
201 views

Why did it take so long to enforce memory permissions?

From the Wikipedia page on DEP. DEP was introduced on Linux in 2004 (kernel 2.6.8[2]), on Windows in 2004 with Windows XP Service Pack 2,[3] while Apple introduced DEP when they moved to x86 in ...
28
votes
2answers
9k views

How do ASLR and DEP work?

How do Address Space Layout Randomisation (ASLR) and Data Execution Prevention (DEP) work, in terms of preventing vulnerabilities from being exploited? Can they be bypassed?